As a large-capacity nonvolatile memory, two-terminal resistance change memories, namely, resistive random access memories have been actively developed in place of a conventional floating gate type NAND flash memory. This type of memory is capable of low-voltage and low-current operation, high-speed switching, miniaturization and high integration of memory cells.
A large-capacity memory array includes a large number of metal wires referred to as bit lines and word lines arranged to intersect each other so as to form a memory cell at an intersection of the bit line and the word line. Writing into a single memory cell is performed by applying voltages to bit lines BL and word lines WL connected to the cell.